
I screwed a good quality square UHF adapter plug (PL-259) to the SO-239 end of one of those surge arresters and the process almost ruined my nice right angle plug because the mating part of the inner conductor became like that pressed tightly against the adapter's inner plug that when plugged in it scraped metal filings from the plug and "wobbled" to put it on the muzzle flash hider (tried to tighten it over a long distance) . it is sufficient for the lugs of the outer conductor to hook/snap into the "prongs" of the socket of the SO-239 arrester so that the plugs do not twist axially against each other). Not twisted, but very difficult (and harmful!) to invent. "Cheap" but poor quality, in my opinion.

VINTAR EU To US Plug Adapter 3-Pack For Easy Travel: Europe To USA Converter For Spain, France, And More, Compatible With Type C/E/F Plugs - European To US Power Adapter Solution
11 Review

HOMELYLIFE 600W High Power Voltage Reducer DC 48V 60V 72V Step Down To DC 12V 50A Buck Converter Waterproof Module Car Truck Power Regulator Transformer
12 Review

DC/DC 12V To 24V Boost Converter 40A 960W - Waterproof Voltage Regulator Module For Car Power Supply (10V-16V Input)
15 Review

Germany France Travel Power Adapter,TESSAN Schuko Plug With 2 USB Ports 2 AC Outlets, US To European Europe German French Spain Iceland Norway Russia Korea Adaptor(Type E/F)
17 Review